Silicon nitride material and making method

摘要

A silicon nitride material in the form of silicon nitride particles which are coated on their entire surface with 0.1% to less than 10% by weight, calculated as oxide, of a water-insoluble metal compound containing a rare earth element, alkaline earth element or aluminum. The silicon nitride material is sinterable into an article which has a very uniform distribution of a grain boundary phase and drastically improved strength at elevated temperatures and can find use as various heat-resistant parts.